排序算法

package a.b.c.mytest;import java.util.Arrays;public class TestSort {/** * 插入排序 *  * @param arr */public static void insertionSort(int arr[]) {int size = arr.length;for (int i = 1; i < size; i++) {for (int j = 0; j < i; j++) {if (arr[i] < arr[j]) {int tmp = arr[j];arr[j] = arr[i];arr[i] = tmp;}}}}/** * 冒泡排序 *  * @param arr */public static void maopaoSort(int arr[]) {for (int i = 0; i < arr.length; i++) {for (int j = 0; j < arr.length - i - 1; j++) {if (arr[j] > arr[j + 1]) {int tmp = arr[j];arr[j] = arr[j + 1];arr[j + 1] = tmp;}}}}/** * 分治法,归并排序 *  * @param arr */public static void mergeSort(int arr[], int start, int end) {if (start + 1 < end) {int middle = (start + end) / 2;mergeSort(arr, start, middle);mergeSort(arr, middle, end);// mergeint left[] = Arrays.copyOfRange(arr, start, middle);int right[] = Arrays.copyOfRange(arr, middle, end);int leftSize = left.length, leftPtr = 0;int rightSize = right.length, rightPtr = 0;for (int i = start; i < end; i++) {if (leftPtr >= leftSize) {arr[i] = right[rightPtr];rightPtr++;} else if (rightPtr >= rightSize) {arr[i] = left[leftPtr];leftPtr++;} else {if (left[leftPtr] <= right[rightPtr]) {arr[i] = left[leftPtr];leftPtr++;} else {arr[i] = right[rightPtr];rightPtr++;}}}}}/** * 堆排序 *  * @param arr */public static void heapSort(int arr[]) {buildHeap(arr);for (int i = arr.length; i > 1; i--) {int tmp = arr[0];arr[0] = arr[i - 1];arr[i - 1] = tmp;maxHeapify(arr, 0, i - 1);}}// 保持最大堆性质private static void maxHeapify(int arr[], int i, int heapSize) {int left = 2 * i + 1;int right = 2 * i + 2;int max = i;if (left + 1 <= heapSize && arr[left] > arr[i]) {max = left;}if (right + 1 <= heapSize && arr[right] > arr[max]) {max = right;}if (max != i) {int tmp = arr[i];arr[i] = arr[max];arr[max] = tmp;maxHeapify(arr, max, heapSize);}}// 构建最大堆private static void buildHeap(int arr[]) {for (int i = arr.length / 2 - 1; i >= 0; i--) {maxHeapify(arr, i, arr.length);}}/** * 快速排序 * @param arr * @param start * @param end */public static void quickSort(int arr[], int start, int end) {if(start < end){    int middle = arr[start];    int left = start;    int right = end;    while(left < right){    while(left < right && arr[right] >= middle){    right --;    }    arr[left] = arr[right];        while(left<right && arr[left] < middle){    left ++;    }    arr[right] = arr[left];    }    arr[left] = middle;    quickSort(arr,start,left-1);    quickSort(arr,left+1,end);}  }/** * 计数排序 * @param arr * @param max */public static void countingSort(int arr[],int max){int c[] = new int[max+1];for(int i=0;i<=max;i++){c[i] = 0;}for(int i=0;i<arr.length;i++){c[arr[i]] = c[arr[i]] + 1;}for(int i=1;i<=max;i++){c[i] = c[i-1] + c[i];}int b[] = new int[arr.length];for(int i=b.length-1;i>=0;i--){b[c[arr[i]] - 1] = arr[i];c[arr[i]] = c[arr[i]] - 1;}for(int i=0;i<b.length;i++){arr[i] = b[i];}}public static void main(String args[]) {int arr[] = { 5, 3, 4, 1, 2 };System.out.println("原数组：" + Arrays.toString(arr));TestSort.insertionSort(arr);System.out.println("插入排序结果：" + Arrays.toString(arr));int arr1[] = { 5, 3, 4, 1, 2, 10, 4, 9, 7, 8 };System.out.println("原数组：" + Arrays.toString(arr1));TestSort.mergeSort(arr1, 0, arr1.length);System.out.println("归并排序结果：" + Arrays.toString(arr1));int arr2[] = { 50, 3, 4, 1, 2, 10, 4, 9, 7, 8 };System.out.println("原数组：" + Arrays.toString(arr2));TestSort.maopaoSort(arr2);System.out.println("冒泡排序结果：" + Arrays.toString(arr2));int arr3[] = { 50, 300, 4, 1, 2, 10, 42, 98, 7, 8 };System.out.println("原数组：" + Arrays.toString(arr3));TestSort.heapSort(arr3);System.out.println("堆排序结果：" + Arrays.toString(arr3));int arr4[] = { 50, 300, 4, 1, 2, 10, 42, 98, 7, 8 };System.out.println("原数组：" + Arrays.toString(arr4));TestSort.quickSort(arr4, 0, arr4.length -1);;System.out.println("快速排序结果：" + Arrays.toString(arr4));int arr5[] = { 500, 300, 4, 1, 2, 10, 42, 98, 7, 8 };System.out.println("原数组：" + Arrays.toString(arr5));TestSort.countingSort(arr5, 500);System.out.println("计数排序结果：" + Arrays.toString(arr5));}}